As above - I have an older RCBS RockChucker press - has a "large" thread in top, then a reducing bushing screwed in that goes down to 7/8" x 14 threads per inch - my former RCBS "JR" press only had the 7/8" x 14 threads on top - we have had dies from 22 Hornet to 458 Win Mag screwed into that reducer - all work fine - brands on shelf include Lyman, RCBS, Lee Precision, Bonanza (!), Hornady - all seem to fit. Besides the die set, you also need the correct shell holder for that cartridge - it goes into the press ram to hold the cartridge to go up into, and pull out of, the die. Is also multiple accessories that screw into those 7/8" x 14 tpi threads - Lyman "M" dies, RCBS collet bullet puller, de-capper, primer pocket swager, plus various Lee Precision Factory Crimp Dies and the Larry Willis collet die.